The Mrs aint gonna be happy about this little project!

[r0bsk1]

So some bypass surgery is now required!
I realised putting the belt through the backplate will put it at risk from swarf. I need to protected it from crap so my plan is to use a FK ballscrew support fixed to the outer of one of the Y uprights with a BF support at the other end mounted to the backplate. There's just about enough room if the FK support is sunk into the plate.
The belt from the stepper would have to come down diagonally due to the stepper being positioned to clear the X screw mount.

Temporary Y stepper mount

Also saves cutting a big ass hole in £100+ piece of tooling plate!
Ill draw it up next if Sketchup decides to open any time soon.